Author Topic: 2 cyl. rotary valve engine  (Read 13354 times)

Offline cidrontmg

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2 cyl. rotary valve engine
« on: May 27, 2010, 06:40:40 PM »
Thereīs another build of a very similar thing atm in HMEM, by max corrigan. Far be it from me to try to steal anyoneīs thunder, Iīll post my widget here. Itīs perhaps also more appropriate here, since I modded the original design to suit what material I had in hand, and to get an even faster runner. These things run real fast, given a pressure of some 50-60 psi (4-5 bar).



side view



As you can see, it has a simpler linkage between the eccentric and valve, to not to rob power in the linkage mechanism. The valve, which is a 8 mm stainless bar with two milled flats, does not really rotate, it  swings back and forth in some 75-80 degree arc, like a windshield wiper axle. A lot faster, though.
Also note the "intake manifold", far simpler than in max corriganīs engine. Itīs just a flat brass bar with a milled cavity inside, to furnish air (steam) to the cylinders.



The puny flywheel has an alum. center and a press-fit bronze ring around, to give some swing mass to it. Way cheaper than a full bronze/brass disk (miser, miser)...

Thereīs also interference-fit bronze liners in the cylinders, similar to Rudy Kouhouptīs compound engine, from which I copied the idea. I built that before this gadget, and bronze liners work real well with alum. pistons. The pistons have grooves (one each) filled with graphite yarn, also suggested by Rudy K. Iīve used also (plumberīs) teflon tape for similar purposes, itīs a good alternative. Graphite is way dirtier, though  :borg:
Another thing you canīt see are ball bearings, they make for a very freely rotating engine. It turns 3 full rotations at a flick of a finger.
You might notice also the "balanced" crank cheeks, the plans call for round disks. Theyīre not really balanced, but I first made them round, and the machine walked right off the table when I gave it some compressed air. So I cut big chunks off both sides of the crank pins, and now at slow speeds anyways, it stays on the table without clamps or screws.
Iīll try posting a video sometime soon, running on compressed air, I donīt have a steam boiler. But I donīt see any reason why it wouldnīt run on steam as well. The only possible rusting parts are the ball bearings and the fly wheel attaching screw. All other steel parts are stainless.

As a side note, I attached this to a hard disk spindle motor, running as a generator. Old hard disks ran at 5000-something rpm, and used 12 V for the spindle. To run one as a generator, you must give it at least the same 5000 rpm, and not expect anything like 12 V back, more like 4-5 V, if that. They must run very fast indeed to get
12 V, Iīd say well over 10 000 rpm, but thatīs just a guess  :smart: And the amps are very meager, just some mAīs.
I have a good stock of huge 10 mm LEDīs that need at least 1.8 V to give any light, with a 1.5 V battery thereīs no emission at all. I connected one of those to the HD motor/generator and gave the engine some (= a lot of) air.  To my surprise, the LED lit up, flickering (the HD generator put out AC), but VERY bright, and after some 5-10 seconds it went off, never to light up again. Hm. I connected 3 LEDs in series, gave gas again, and I had 3 LEDs flickering  :med:
That wasnīt for very long, though (several minutes), the engine would need oil  (WD-40), and thereīs no provision for it when running. But it was nice to see anyway  :zap:


Olli
Penafiel
Portugal

Offline dsquire

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Re: 2 cyl. rotary valve engine
« Reply #1 on: May 27, 2010, 07:29:21 PM »
cidrontmg

Nice to see that you have got a running engine there. The fact that you can power a generator off it as well is very interesting. I guess that the next thing will probably be an lubrication system so that you can run it for longer periods of time. I'll be watching for the video when you get it up and posted. You have made a fine job on this and can be very proud of it. Thanks for showing it to us all.  :ddb: :ddb: :D :D

Cheers  :beer:

Don
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and your better best

Offline HS93

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Re: 2 cyl. rotary valve engine
« Reply #2 on: May 27, 2010, 07:33:08 PM »
that looks great , its nice to see somethink different have you got any sketches or pictures of the valve gear.

is it self starting ??

thanks

peter
« Last Edit: May 27, 2010, 07:35:30 PM by HS93 »
I am usless at metalwork, Oh and cannot spell either . failure

Offline Bernd

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Re: 2 cyl. rotary valve engine
« Reply #3 on: May 27, 2010, 09:19:59 PM »
Nice engine. :thumbup: Very simple and a nice mod too.

My Dad built one of those many many years ago at the place of his emplyoment. I'll have to dig it out and see if it still runs. As I recall it was quite heavy.

Bernd
Route of the Black Diamonds

Offline cidrontmg

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Re: 2 cyl. rotary valve engine
« Reply #4 on: May 27, 2010, 10:10:57 PM »
HS93: The plans (and the valve functions) are here

http://www.john-tom.com/MyPlans/Steam%20Engines/RotaryValveEngine.pdf

I guess it was originally published in Popular Mechanics, a long time ago. At least they used the same type font, but I think so did many other publications.
Itīs not a self-starter, neither does it reverse. To reverse, it would need another valve bar, with the milled slots in mirror image, and changing the exhaust passages. Thatīs why there are, in my machine, 4 exhaust holes, instead of the 2 that are needed. The 2 "extra" holes have screwed plugs in them, and the "real" exhausts have similar plugs with a hole in them. I also have a mirrored valve bar, and Iīve had it working both ways. In fact I made several valves, trying to get a fast runner with little air. Thereīs still plenty of room for optimization, but Iīve built many engines since then. When I got the LEDs lighted with it, that was good enough, and to the shelf it went.
Olli
Penafiel
Portugal

Offline HS93

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Re: 2 cyl. rotary valve engine
« Reply #5 on: May 27, 2010, 11:48:14 PM »
thank you for that.

Peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline cidrontmg

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Re: 2 cyl. rotary valve engine
« Reply #6 on: June 11, 2010, 04:58:28 PM »
Finally I found a camera that does some sort of a video. My own camera is atm in England with my son, the second camera I tried was broken, and this is the oldest camera in our household that basically is a still camera, but puts out 45-sec. clips of video also, at abt. 15 frames/sec... And no sound  :(
Seems I have to buy yet another video camera   :scratch:
 The quality is rather poor, and I upped it to Photobucket, so it might not even work for everyone. Oh well...
The machine is very free-running, at first it starts with some 0.2 bar, running slowly, then I give it 0.8 bar and itīs a blur, doing some 2200-2300 rpm. Iīve ran it with 3 bar, it did some 5500-6000 rpm, and was on the point of self destruction. Itīs not too well balanced as you can (hopefully) see, with 3 bars, it was held in a bench vise  :D

Olli
Penafiel
Portugal

Offline sbwhart

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Re: 2 cyl. rotary valve engine
« Reply #7 on: June 12, 2010, 01:19:01 AM »
Nice Engine runs real well  :thumbup: :thumbup: :thumbup: :thumbup:

:clap: :clap: :clap: :clap:

Thanks for showing

Stew
A little bit of clearance never got in the road
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Location:- Crewe Cheshire